Blog for FrancoisOrsini

Tuesday Sep 22, 2009

Kristian Wagaan and Richard Hillegas, both Apache Derby committers who also work on Java DB, recently gave some great presentations about Apache Derby and Java DB.

Kristian Wagaan presented at the 2009 OpenSQLCamp, in conjunction with FrOSCon 2009 in Europe.

The presentation (slides) gives a brief overview of Apache Derby, its history and the community around it. Further, it goes into the details of features that have been added in the latest releases and show how they enable powerful ways to use a relational database.

Rick Hillegas gave an introduction of Java DB / Apache Derby at The San Francisco Java User Group's Sep 8th event in San Francisco.

Monday Sep 14, 2009

Java DB 10.5.3 is primarily a bug-fix release and inherits all the bug fixes and localized messages from Apache Derby 10.5.3.

Java DB offers installers for the following platforms:

Solaris

Linux

Windows

Mac OS X (newly added)

Here is a recap of all changes that are coming as part of Java DB 10.5.3:

SQL Roles - SQL roles (as described in SQL
2003 and errata) are useful for administering privileges for groups of
users. Administering roles is generally less error-prone than
administering privileges for individual users. SQL Roles are defined in
Feature T331 "Basic roles" and Feature T332 "Extended roles". Java DB
10.5 implements a subset of T331, plus support for CURRENT_ROLE, which
is a part of T332.

Generated Columns - Generated Columns is a
feature which instructs Java DB to fill a column with an expression
built out of other columns in the row. Java DB constructs these column
values at INSERT and UPDATE time. The user declares indexes on these
columns. This in turn improves SELECT performance since it lets users
declare indexes on pre-computed pieces of the WHERE clause. This
feature satisfies support for SQL Feature T175.

LOB Improvements - There were many performance and usability improvements for BLOBs and CLOBs.

Replication of encrypted databases - With 10.5 it is possible to replicate encrypted databases.

OFFSET/FETCH FIRST - SQL 2008 has added new
syntax to support a direct way to limit the returned set of rows in a
result set, through the fetch first and offset clauses.

In-memory back end - Initial implementation of
a storage engine for Java DB where all data is kept in memory. There is
no documentation for this feature. This functionality itself is not yet
fully implemented, but users are welcome to experiment with it. For
details, see the Primer for In-memory Back Ends.

SYSCS_UTIL.SYSCS_UPDATE_STATISTICS -
New system procedure that updates cardinality statistics (or creates
them if they do not exist) for a table's index or for all the indexes
on a table, allowing a user to ensure that a query plan based on the
most recent state of the table can be created.

Service tag - Introduction of the Java DB registration service (service tag).

Further details on new features, changes, and issues in this release can be found in the Release Notes.